Multilayer gaskets such as multilayer metal gaskets are becoming increasingly more popular for use with automobile engines. Such gaskets are typically comprised of two or more layers which are secured to each other, as by clinching tabs or the like. Each gasket layer may be similar in general size and overall configuration to the other layers. Each layer can, however, include details which importantly distinguish it from the other layers, such as by having one or more embossments provided thereon, while another similarly configured gasket layer in the same gasket assembly may have different embossments or other significant features. Additionally, for example, one layer in the assembled, multilayer gasket may be substantially flat while another layer in the same gasket may include embossments, coatings and the like.
Production of multilayer gaskets typically comprises multiple steps. First, because each layer comprising the assembled gasket typically may be uniquely configured, the individual gasket layers are mass produced, as by a stamping or blanking process. The individual gasket layers may also be suitably processed, as by heat treating, with coatings, etc., as may be appropriate. Once completed, the individual gasket layers are assembled in a specific sequence and subsequently are secured in that sequence. After the separate gasket layers have been secured as a complete assembly, the resultant gasket is inspected for accuracy and compliance.
It is critical that each layer comprising the multilayer gasket be assembled in its proper order. Otherwise, the assembled gasket is likely to fail. Because the layers comprising the gasket may all be generally similar in size and overall configuration, assembly of the gasket can easily be done incorrectly. That is, gasket layers may be arranged in an improperly layered order. Alternatively, and because the gasket layers are individually manufactured, stacked, and then assembled, two of the same gasket layers may be inadvertently assembled together. A myriad of other inadvertent and incorrect combinations of gasket layers is conceivable. Such improper combinations or arrangements of the various gasket layers can result in gasket and engine failure.
Various efforts have been made to avoid such problems. One such approach is embodied in U.S. Pat. No. 4,813,691 which is commonly owned with the present application. Another is shown in U.S. Pat. No. 4,648,607.
It would be of advantage to provide a multilayer gasket which has the multiple layers assembled in a verified, proper sequence prior to securing them together to guarantee that the gasket will function correctly and to avoid waste of gasket layers which, if assembled incorrectly, will likely become scrap.